Field of the Invention
The present invention relates to a method for distributing digital codes converted from video signals and recorded on a plurality of channels on a recording medium utilizing magnetism, lights, or the like.
A digital VTR is an example of an apparatus in which video signals are converted into digital codes to be recorded on a medium by use of magnetism, lights, or the like. Since the codes obtained from the video signals yield high-speed data having a transfer rate of at least 100 Mb/s, it is very difficult to record the codes with a magnetic head, for example. In order to overcome this difficulty, there has been employed a technique which allows the codes to be distributed to a plurality of channels so as to record the codes in a parallel fashion by using a plurality of magnetic heads at the same time.
The following three methods for distributing video codes have been well known as described in "A Study on Variable Speed Reproduction of the Digital VTR", Y, Hirano et al., SMPTE Journal, Vol. 92, No. 6 (June 1983), pp 636-641. For example, the video codes are distributed to channels A, B, and C as follows.
1. For each pixel, the high-order, intermediate, and low-order bits are distributed to channels A, B, and C, respectively.
2. For every three consecutive pixels, operations are repeated for the channels as A, B, C; A, B, C; and so on.
3. The pixels in the left-hand side area, the central area, and the right-hand side area of the screen are distributed to channels A, B, and C, respectively.
In the publication article described above, however, the channel distribution was mainly considered for signals (so-called composite signals) in which the luminance and color signals are multiplexed in accordance with a frequency division like the NTSC signal.
On the other hand, to record a high-quality picture, it has been believed that each component signal should be respectively recorded without multiplexing the luminance and color signals by use of the frequency division. Any examples have not been known yet in which the optimization of the channel distribution with respect to so called component signal system has been described.